Method of treating a producing formation



Amig. 29, 1939. R. E. LEE

METHOD 0F TREATING A PRODUCING FORMATION Filed Feb. 23, 1937 @Egg INVENTOR.

ATTORNEY.

IIIIIIIIII `Patented Aug. 29, 1939 UNITED STATES UDCH Lilli PATENT OFFICE LIETHOD 0F TREATING A PRODUCING FORMATION Robert E. Lee, Coleman, Tex., assigner to Lee Angular Drill Corporation, Dallas, Tex., a corporation of Delaware Application February 23, 1937, Serial No. 127,028

3 Claims.

'I'his invention relates to a method of chemically treating,shooting and repressuring wells and it has particular reference to a method which provides for specifically locating the acid or other chemical, explosive charges and other effective agents in and about the bottom of the hole.

` The principal object of the invention is to provide rst: the step of boring a hole in the earth; second, the step of enlarging the communicating area of the bore hole at its bottom by providing a series of radial or annular channels from the axis of the bore hole into the formation adjacent the bore hole at various levels; third, in packing 01T selective groups of channels at predetermined levels and in charging said selective groups of channels with a prescribed medium such as acid or other chemicals, explosive charges, Water, gas or the like, for the purpose of renewing or increasing the iiow of liquid from the well.

Yet another object of the invention is to provide a method, which includes the step of channeling and treatment, for replenishing the natural pressure medium in oil and gas producing formations wh'ere such medium has been exhausted or diminished, over Wide areas, by excessive Withdrawals of this necessary prerequisite to production Broadly, the invention anticipates a method for drilling wells which includes the step of angularly drilling at the bottom of the hole to enlarge the productive area of the well and which step shall include the drilling of angular channels as a continuation of the first step of boring the initial hole, as well as channeling wells whose production has ceased or diminished. Also, the invention is effective, through the step of introducing chemicals, explosive charges, Water, gas and the like, into said channels, in further increasing the production since to introduce acid in the channels, a more extensive and uniform drainage area of the formation is effected than could be obtained by present methods, where only the length of the bore hole wall is aiTected.

With the foregoing objects as paramount, the invention will be seen as possessing other salient features and novel steps of the method hereindescribed and illustrated in the accompanying drawing, wherein:-

Figure 1 is a vertical section through a well showing the angular channels and means for introducing acid or other medium into the channels.

Figure 2 is a section on lines 2-2 on Figure 1, and

Figure 2 illustrates a means for packing off selective channels at predetermined elevations.

Continuing with a more detailed description of the invention, reference is primarily made to Figure 1 which shows the conventional well cas- 6 ing I, in which is disposed the conventional tubing 2, both being in vertical section.

The present invention deiines an improvement over the claims of my Patent No. 1,816,260 in that in this patent, repressuring of wells is effected 10 and is obtained by recirculation of a repressuring medium through upper and lower angular or lat-` eral channels and out of the well through a discharge pipe or tubing. This invention seeks to define a method for acidizing, shooting or re- 15 pressuring wells Where the effectiveness of these operations depends upon channeling or otherwise increasing the ow of liquid from a well, Without recirculation. Accordingly, the first step of the present invention comprises the step of drilling 20 the well and then in drilling the series of channels 3, after which the vertical bore or Well is deepened and another group of angular channels or openings 4 are drilled at a level below that of the rst group 3. The casing I is set in the 25 usual manner and the tubing 2 is run to a point below the terminal of the casing, and is provided with a series of apertures, windows or perforations 5.

A liquid or fluid medium such as acid or other 30 chemical, Water or gas is introduced by gravity or pressure by means of a pump 6, (Figure 3) through the line l, into the tubing 2, into the well and upon reaching the bottom of the bore l hole, the medium ilows into the lateral or angular channels 3 and 4, where it acts upon or alects the formation according to the purpose intended therefor.

In order, however, to place an explosive charge in one, several or all of the channels 3 and 4, the tubing 2 is required to be withdrawn so that a liqueed or solidified explosive charge may be lowered and directed into the channel or channels to be thus treated, in a uniform manner, after which the charge is set off.

When it is4 desired to treat or acidize channels at a predetermined level, the expansion packer 8, such as shown in Figure 3 is provided and may be of the conventional self expansion design. 5 This packer is so disposed on the 'tubing string 9 that when the tubing extension I0 is set down upon the bottom of the hole I I', it expands against the walls of the hole to separate the upper channel group I2 from the lower channel group I3. 55

ililUUlll A shoe I 4 is provided upon the lower end of the pipe string I0, as shown.

Accordingly, when the shoe I4 reaches the bottom of the hole II, and the weight of the string expands the packer 8, closing the hole against passage of the treating medium to the lower channels I3, only the upper series of channels I2 receive the treating medium which is passed downward by gravity or pressure of pump 6, through pipe I5, and ports I6 in the reversible `joint I1, and into the upper series of channels I2, without affecting the lower series of chan nels I3.

It will be observed that the joint II is threaded onto the lower end of the tubing string in Figure 3. This feature enables the joint to be inverted and threaded onto thel bottom of the packer 8, so that the ports I6 will be exposed to the lower series of channels I3 and in order that the treating medium will not rise in the hole, and flow into the upper series of channels I2 when it is desired to treat the lower series. It will be Iunderstood that the pipe string is removed from the bore hole after treating a group of channels preparatory to inverting th'e joint I1 for treating another group of channels.

Thus, the groups of channels may be treated collectively or separately, as required by employing the packer or dispensing with it entirely as shown in Figure 1.

A distinct advantage, however, in using the packer lies in the fact that the upper series of channels I2 may be acidulated to dissolve calcareous substance, limy and other formations detrimental to fluid ow, after which a pressure medium is forced into the lower series of channels and which latter medium will be effective to expel dissolved matter from the treated channels and out of the drainage area of the bore hole. 'I'his operation may be inversely applied, as apparent.

It is apparent from the foregoing that productive areas of wells and entire lields where salt water and other natural pressure mediums have been depleted, may again be made productive by the present method which has been successfully practiced over a wide area of oil and gas producing regions.

Also, in the art of geophysical prospecting, explosive charges are placed in bore holes in predetermined spaced relationship, exploded and the resulting Waves seismographically intercepted and recorded. The present invention affords an advantage in this practice in that shots may be uniformly placed in the angular channels and the vertical bore hole suitably plugged to prevent interference by the objectionable ground waves when the charges are exploded on or near the earths surface. Thus, a more intelligible and comprehensive record of the tectonics of the earth may be obtained.

Manifestly, the construction of the apparatus and the steps of the method described herein are capable of considerable modification and such modication as is considered within the scope and meaning of the appended claims is also considered within the spirit and intent of the invention.

What is claimed is:

1. The method of acidizing petroleum producing formations which consists initially in boring a vertical hole, then in drilling a plurality of angular openings at predetermined levels and angles from and with respect to the vertical bore hole, in packing off selective groups of said openings, in introducing into unrestricted groups of openings an acidizing agent through said bore hole, in changing the position of the discharge point of said agent with respect to the packing to obtain access to companion groups of openings and in introducing thereinto said acidizing agent.

2. The method af acidizing, chemically treating and repressuring a petroleum. producing earth formation, characterized by boring a hole into said formation and in drilling a plurality of angular openings at predetermined levels and angles from the bore hole, in packing o selective groups of said openings, in introducing into the unrestricted groups of openings a treating reagent through said bore hole, in changing the discharge point of the reagent with respect to the packing to elfect ingress into the formation to adjacent groups of openings, and in impressing fluid pressure upon the-treating reagent,

3. The method of increasing the porosity and productivity of an oil and gas producing formation characterized by drilling vertically into said formation, in drilling angular openings into said formation at substantially right angles to the l 

